If you're visiting San Juan for more than three days, I highly recommend getting out of Puerto Rico's capital and exploring other parts of the island. The good news is, you don't have to take an expensive tour group to see some of Puerto Rico's greatest assets. Here are just a few ideas to get you going.

Visiting any one of Puerto Rico's myriad beaches can make for a fun day trip away from the city, but as there is plenty of beachfront in San Juan, it's been left off this list of cheap excursions.

This is an obvious one because one of Puerto Rico's greatest draws is absolutely free. The El Yunque National Rainforest is a lush green oasis with several hiking trails, a spectacular waterfall and plenty of scenic vistas to enjoy. You have to get there, and if you want to avoid taking a tour, which can cost around $30 to $40 per person, consider renting a car for the day. It's worth the effort because you can combine the free rainforest with the free Luquillo Beach and the very cheap kiosks on the way for some serious roadside snacking.

There is a cheap way to get to the wonderful islands of Vieques and Culebra, but it will take you a while. Here's the four-step process:

Grab a público to Fajardo. It's cheap, but it will take a few hours. If you're willing to splurge, a taxi can cost between $25 to a lot more depending on traffic.

Take the public ferry to the island of your choice. Make sure you check with the Puerto Rico Maritime Authority (787-863-0705) for the schedule and time your trip accordingly. Again, it's cheap but it takes more time than flying.

Given how close it is, and throw in the free trip if you're dining at Soleil Beach Club, and it's hard to beat Piñones for value. The great beach is free, the plethora of kiosks nearby offer a great diversion, even if you don't eat anything there, and it's a different vibe in this rustic retreat.

Patron Saint Festivals, or Fiestas Patronales, as they are locally known, are an explosion of local flavor, pageantry, and culture. These are festivals held by most towns around the island to honor their patron saint, and they comprise a day (or more, depending on the town) of music, parades, food, and general frivolity. This is another great use for the públicos, which is how Puerto Ricans who don't have cars get to and from the small towns to the big cities. Before you plan your trip, check the schedule for patron saint festivals and know where you're going.

Far less famous and less visited than Puerto Rico's other big forest, the Guánica State Forest is just as unique as El Yunque. Located in the Southwest near the city of Guánica, this is believed to be the best preserved subtropical dry forest in the Caribbean. It's also home to roughly half of Puerto Rico's species of birds and over 700 plant species, of which almost 50 are endangered. There are well-made trails to take you to the forest, and like El Yunque, your biggest expense will likely be getting here. A rental car should take care of that.